Method and apparatus for regulating the temperature of a form bed running on guideways in a flat bed letter press printing machine

ABSTRACT

Method of regulating the temperature of a form bed running on guideways in a flat bed letter-press printing machine includes measuring the temperature of the form bed, comparing the measured form bed temperature to a given nominal value, and selectively precooling and preheating lubricant supplied under pressure and from below to the guideways for the form bed so that the temperature of the form bed corresponds substantially to the given nominal value during operation of the printing machine; and apparatus for carrying out the method.

United States Patent Inventor Hubert H. A. Sternberg Heidelberg, GermanyAppl. No. 812,572 Filed Mar. 28, 1969 Patented June 15, 1971 AssigneeHeidelberger Druckmaschinen Aktiengesellschaft Heidelberg, GermanyPriority Mar. 30, 1968 Germany P 17 61 076.3

METHOD AND APPARATUS FOR REGULATING THE TEMPERATURE OF A FORM BEDRUNNING ON GUIDEWAYS IN A FLAT BED LETTER PRESS PRINTING MACHINE 12Claims, 4 Drawing Figs.

US. Cl 165/2, 165/27, 165/48, 101/250 Int. Cl F25b 13/00 Field of Search165/2, 27, 61,48; 101/250 [56] References Cited UNITED STATES PATENTS2,896,532 7/1959 Buttner 101/250 3,202,096 8/1965 Ranger 101/2503,480,076 11/1969 Tamita 165/27 Primary Examiner-Charles SukaloAttorneys-Curt M. Avery, Arthur E. Wilfond, Herbert L.

Lerner and Daniel J. Tick pmimmumsmn BBB/L681 SHEU 1 OF 2 METHOD ANDAPPARATUS FOR REGULATING THE TEMPERATURE OF A FORM BED RUNNENG ONGUHDEWAYS TN A FLAT BED LETTER PRESS PRINTING MACHTNE My inventionrelates to method and apparatus for regulating the temperature of a formbed running on guideways in a flat bed letter-press printing machine.

To reduce the inertial forces which are produced by the reciprocatingmovement of the form bed in a flat bed letterpress printing machine, itis known to make the form bed as light as possible either by providingit with a suitable shape employing a minimum of structural material orby using a structural material in the production thereof which has a lowspecific weight.

It is also known to guide the form beds accurately in the longitudinaldirection thereof and in a horizontal plane on guide rails, guiderunners or skids or similar members. These guide members must thereby,at least in part, absorb very great forces, especially during theprinting operation proper, and also due to the added dynamic forcesarising from the drive mechanisms and determined by the type of drive.

The very frequently employed system of guiding the type foundation orbed on roller members for absorbing the forces applied verticallydownwards demands a high degree of preci sion in manufacture due to thestatic indefiniteness or uncertainty of those forces. The roller membersthemselves often do not carry out a purely rolling motion, but rather,experience added movements, determined by their own inertia, which aremanifested in a sliding motion that is superimposed on the rollingmotion. The consequences thereof are the formation of ripples in theguideway, wear and tear and the development of a loud noise.

The conventional guideways first mentioned hereinabove have thedisadvantage that the frictional forces occurring due only to slidingare considerably higher than the rolling friction forces of the rollerguides, especially since the formation of hydrodynamic lubricant filmsis impossible or is possible only to a very moderate extent because ofthe reversal in the direction of movement of the form bed. The increasedfrictional output necessarily leads to the development of heat, which istransmitted to the machine component being guided, namely the form bed.Also, in spite of the much smaller frictional output when a so-calledhydrostatic lubricant is used, heat is produced due to the choke orthrottling losses of the lubricant which is supplied under pressurethrough very narrow gaps. This heat also is transmitted in part to theform bed. As a consequence of these heat formations, the form bed experiences dimensional changes depending respectively upon the shape andmaterial of the form bed. These changes also effect the type form on thebed and ultimately impede or render impossible maintenance of positionalaccuracy from one printing pass to another.

The fact that the light metals have more than double the thermalcoefficients of expansion than the otherwise commonly used cast ironalloys must then be considered in light of the foregoing, since theintended employment thereof for reducing the inertial forces of the formbed is thus rendered difficult due to the aforementioned disadvantagederiving from the very high coefficients of expansion thereof.

It is accordingly an object of my invention to provide method andapparatus for regulating the temperature of a form bed running onguideways in a flat bed letter-press printing machine which avoid theaforementioned disadvantages of the heretofore known form beds and flatbed letter-press printing machines. More particularly, it is an objectof my invention above all to prevent temperature changes in the form bedirrespective of the particular material thereof. 1

With the foregoing and other objects in view, I provide method ofregulating the temperature of a form bed running on guideways in aflatbed letter-press printing machine which comprises measuring thetemperature of the form bed, comparing the measured form bed temperatureto a given nominal value, and selectively precooling and preheatinglubricant supplied under pressure and from below to the guideways forthe form bed so that the temperature of the form bed correspondssubstantially to the given nominal value during operation of theprinting machine.

Frictional heat produced in the guideways or the temperature dropsoccurring in the working space of the flat bed letter-press printingmachine cannot therefore have a disadvantageous effect on themaintenance of accurate registry between sequential printing passes,since no change occurs in the shape of the form bed and thereby in theform or type face proper due to thermal effects.

The apparatus of my invention carries out the foregoing method andcomprises means for measuring the temperature of the form bed, means forcomparing the form bed temperature to a given nominal value, and meansfor selectively precooling and preheating lubricant supplied underpressure and from below to the guideways so that the temperature of theform bed corresponds substantially to the given nominal value duringoperation of the printing machine.

In accordance with additional features of the apparatus of my invention,I provide a cooling device and/or a heat exchanger device connected in acircuit in which the lubricant is supplied to the guideways. Thelubricant which forms a supporting film for the form bed running on theguideways is regulated to a substantially constant temperature by one orthe other or both of the aforementioned devices, the regulatingdeviation necessary for maintaining the stability of the regulatingcircuit being only a few degrees centigrade. A regulating deviation offor example 5 C. effects no change in the type form which mightintroduce difficulties in setting the form in proper registry.

in accordance with another feature of my invention, a temperaturesensing member is provided at a location of the lubricant circulatingsystem downstream of the guiding or sliding surfaces of the guideway andform bed for determining the temperature of the lubricant at thatlocation. Also provided is a comparator device in which the measuredtemperature value is compared with a given nominal temperature valueand, in response to a difference therebetween, the comparator effects achange, through the cooling and heat-exchanging devices, in thetemperature of the lubricant issuing from the heat exchanging device sothat the temperature of the discharging lubricant remains independent ofthe load within the limits of permissible control deviation. Normally,the discharging lubricant is to be cooled and then returned at a lowertemperature to the guiding or sliding surfaces. At the beginning ofoperation as well as for large temperature deviations in the workingspace and under conditions depending upon the respective choice of theonce established temperature level, an occasional temporary heating ofthe lubricant may also be advantageous or necessary.

In accordance with a further feature of my invention 1 provide acirculating system wherein a temperature controlled orquantity-controlled coolant flow circulates, the coolant taking no partin the formation on the guideways of a form bed-supporting lubricantfilm. The coolant flows through closed channels adjacent the guiding orsliding surfaces of the guideway and thereby maintains the guideway atsubstantially the same temperature. The temperature of this coolant flowis then independent of the load and facilitates maintenance of thetemperature level at a constant value. The coolant paper can in thiscase be a different medium than that necessary for maintaining asupporting lubricant film.

when using the same medium for cooling as for lubricating, the closedchannels can be dispensed with, and the vicinity of the sliding orguiding surfaces can be kept at a constant temperature directly as byspraying with the lubricant for example. The quantity or the temperatureof the additionally supplied lubricant is thereby able to be varied inaccordance with requirements.

The aforedescribed manner of controlling the temperature of thelubricating medium proper can be utilized by itself alone or alsotogether with the method described in the next preceding paragraph.Control of the temperature according to the latter method alone is alsoconceivable.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin the method and apparatus for regulating the temperature of a form bedrunning on guideways in a flat bed letter-press printing machine, it isnevertheless not intended to be limited to the details shown, sincevarious modifications and structural changes may be made therein withoutdeparting from the spirit of the invention and within the scope andrange of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings, in which:

FIG. I is a diagrammatic elevational view of a flat bed letter-pressprinting machine;

FIG. 2 is a sectional view taken along the line AB in FIG. I and showsschematically a circulating system wherein the flow of lubricantissimultaneously employed for cooling the flat form bed;

FIG. 3 is the same sectional view as in FIG. 2 of another embodiment ofthe invention and shows schematically a circulating system wherein aseparate coolant flow is provided; and

FIG. 4 is the same sectional view as in FIGS. 2 and 3 of yet anotherembodiment of the invention and shows schematically a circulating systemwherein there is branching of the flow of lubricant, one of the branchesbeing employed exclusively for cooling the form bed.

Referring now to the drawings and first particularly to FIG. 11 thereof,there is shown in elevational view a flat bed letterpress printingmachine having a base frame 1 on which a fiat form bed 2, a printingmechanism 3 and an impression cylinder 4 are mounted. The just-mentionedcomponents 2 to 4 of the flat bed letter-press are of conventionalconstruction and are conventionally mounted on the base frame 1. Theirspecific structure and manner of mounting form no part of the inventionherein and are therefore not further described. The form bed 2 isreciprocable by a conventional nonillustrated drive mechanism onguideways 5 of the base frame 1, two different positions of the form bed2 being indicated by solid and phantom lines in FIG. I. As the form bed2 is reciprocated on the guideway 5 it passes the inking rollers of theinking mechanism 3 and the impression cylinder 4. The guideways 5 of thebase frame I are provided with ducts 6 below the impression cylinder 4.Pressurized oil is supplied through the ducts 6 to the guideways 5 andserves both for lubricating the guideways as well as for cooling the bed2. A cooling system 7 and a heat exchanger 8 belonging to a circulatingsystem for the lubricant oil are mounted within the base frame 1. A moredetailed description of different embodiments of the lubricant andcoolant circulating system of the invention are described hereinafter inconjunction with FIGS. 2 to 4 of the drawings.

FIG. 2 shows only a portion of the entire cross section of the guideways5 and of the form bed 2 sliding thereon. In each guide rail 9 of theguideway 5 there is provided a pressurized oil duct 6 through which thelubricant is conveyed under pressure into the gap 10 located between theform bed rails 11 and the guide rails 9. The lubricant flows through thegap 10 into a discharge chamber 12 and from the latter to the heatexchanger 7 which is suitably coupled to a conventional coolingapparatus 8. After the lubricant has flowed through the coolingapparatus 8, it is forced by the pump 13 again into the duct 6.

A temperature sensing member 14 is mounted in the discharge chamber 12and determines the temperature of the discharging lubricant therein, themeasured temperature value being transmitted to a conventionalcomparator 15 wherein it is compared with a given nominal temperaturevalue. Control of the cooling apparatus is effected by the nominal valuecomparator l5.

If, for example, the lubricant is heated as it flows through the ducts6, the gap l0 and the discharge chambers 12, so that the temperaturethereof in the discharge chambers 12 exceeds a given nominal value, thenominal value comparator 15 accordingly actuates the cooling apparatus 8to cool the discharging lubricant in the heat exchanger '7. Thus, forexample, the comparator 15 may suitably transmit a signal which trips aswitch that energizes a pump in the cooling apparatus 3 which will thencause a suitable coolant to circulate through the heat exchanger 7. Onthe other hand, if the temperature of the lubricant passing from thegaps l0 into the discharge chambers 12 is lower than the given nominalvalue, the comparator 15 will signal the cooling system to reduce thecooling of the lubricant passing through the heat exchanger 7, or infact, actually heat the passing lubricant. To effect an acceleratedreturn flow of the lubricant discharging from the gaps Ml, an additionalpump 16 may be provided in the lubricant circuit. The dimensions of thedischarge ducts must be kept at such values that a relatively rapidreturn flow of the heated or cooled lubricant is possible.

In the embodiment of FIG. 3, it may be assumed that the lubricant passesthrough the ducts 6, the gap l0 and the discharge chambers 12 in asimilar manner as in the embodiment of FIG. 2 except that it does notpass through a heat exchanger. Instead, a separate coolant circulatingsystem is provided for cooling the lubricant. Thus, coolant is passedthrough suitably formed ducts 18 in the guidcways 5, the ducts. 18extending adjacent the ducts 6 for the lubricant in the guide rails 9 ofthe base frame A temperature sensing member 14 determines thetemperature of the coolant in the circulatory loop 17 upstream of a heatexchanger 7, transmits the measured value to a comparator 15 wherein themeasured temperature is compared to a given nominal temperature, asignal being transmitted therefrom to suitably control the coolingapparatus 8 and/or the variable pump 19. The pump 19 forces the coolantthrough the ducts 18. The embodiment of FIG. 3 has the advantage that acoolant can be selected which need not have any of the properties orcharacteristics of lubricants. If necessary, the additional coolantcirculating system of FIG. 3 can be connected parallel to the cooledlubricant circulating system of FIG. 2.

In FIG. 4 there is shown the lubricant circulating system shown in FIG.2, including the pump 13 connected downstream of the heat exchanger 7 inwhich the lubricant is cooled by the cooling system 8. The lubricant inthe embodiment of FIG. 4 is forced by the pump I3 through the ducts 6into the gaps 10 and thence into return flow or discharge chambers 12'located upstream of the heat exchanger 7, the temperature of thelubricant in the chambers 12 being determined by the temperature sensingmember M which transmits the measured value for comparison with a givennominal value in the comparator 15 which accordingly controls thecooling action of the cooling system 8. The embodiment of FIG. 4 differsfrom that of FIG. 2 in that the lubricant flow in the FIG. 4 embodimentdivides downstream of the heat exchanger 7, and an additional andvariable pump 16 forces the thus branching lubricant flow into nozzles29 that are provided adjacent the discharge chambers 12 in the guideway5 of the base frame 1. Cooling chambers 21 that are formed in the formbed 2 are located opposite the nozzles 20. The lubricant in thebranching flow thereof is thus sprayed out of the nozzles 20 into thecooling chambers 21 and flows back through the discharge chambers 12' tothe heat exchanger 7. By intensively spraying large parts of the formbed 2, an especially effective temperature regulation is made possible.

The temperature of the lubricant discharging from the chambers 12 ofFIG. 4 or of the coolant according to the embodiment of FIG. 3 need onlycorrespond approximately to the given nominal temperature value. Acontrol deviation of about 5 C. promotes the stability of the controlcircuit. To

facilitate the control process, the output or delivery of the pump 13can be variable so that by merely controlling the delivered quantity, aspecific temperature constancy is assured.

lclaim:

1. Method of regulating the temperature of a form bed running onguideways in a flat bed letter-press printing machine, which comprisesmeasuring the temperature of the form bed, comparing the measured formbed temperature to a given nominal value, and selectively precooling andpreheating lubricant supplied under pressure and from below to the formbed and the guideways for the form bed so that the temperature of theform bed corresponds substantially to the given nominal value duringoperation of the printing machine.

2. Apparatus for regulating the temperature of a form bed running onguideways in a flat bed letter-press printing machine comprising meansfor measuring the temperature of the form bed, means for comparing theform bed temperature to a given nominal value, and means for selectivelyprecooling and preheating lubricant supplied under pressure and frombelow to the guideways and to the form bed so that the temperature ofthe form bed corresponds substantially to the given nominal value duringoperation of the printing machine.

3. Apparatus according to claim 2 comprising a circulating system forthe lubricant including a cooling assembly, said circulating systemhaving means for conveying the lubricant to the guideways and forforming a supporting lubricant film thereon, said means for selectivelyprecooling and preheating the lubricant being operatively connected tosaid cooling assembly for regulating the temperature of the lubricant atan approximately constant temperature whereby the regulating deviationnecessary for maintaining stability of the system is only a few degreescentigrade.

4. Apparatus according to claim 2, wherein said cooling assemblyincludes a heat exchanger.

5. Apparatus according to claim 3 including a temperature sensing memberprovided at a location in said lubricant circulating system downstreamfrom the surfaces of the guideway on which said lubricant film is formedfor determining the temperature of the lubricant at said location,comparator means operatively connected between said temperature sensingmember and said cooling assembly for comparing the temperature sensed bysaid sensing member with a given nominal temperature and, in responsethereto, actuating said cooling assembly to vary the temperature of thelubricant downstream therefrom so that the measured temperature remainsindependent of the load within the limits of permissible controldeviation.

6. Apparatus according to claim 2 comprising a circulating system forthe lubricant having means for conveying the lubri cant to the guidewaysand for forming a supporting lubricant film thereon, and a circulatorycooling system including closed channels for circulating a lubricantcoolant into and out of proximity of the guide surfaces of saidguideways, said circulatory cooling system including a cooling assembly,said means for selectively precooling and preheating the lubricant beingoperatively connected to said cooling assembly for regulating thetemperature of the lubricant in said lubricant circulating system at anapproximately constant value.

7. Apparatus according to claim 6 wherein the flow of coolant in saidcirculatory cooling system is temperature regulated.

8. Apparatus according to claim 6 wherein the flow of coolant in saidcirculatory cooling system is quantity regulated.

9. Apparatus according to claim 3 comprising a circulating system forthe lubricant having means for conveying the lubricant under pressure tothe guideways and for forming a supporting lubricant film thereon, and acooling system for directly applying to the guide surfaces of saidguideways a temperature-regulated coolant in the form of the lubricantin said lubricant circulating system.

10. Apparatus according to claim 9 wherein said cooling system includesmeans for spraying said lubricant coolant into said lubricant circulatinsystem.

11. Apparatus accor mg to claim 3 comprising a circulating system forthe lubricant having means for conveying the lubricant under pressure tothe guideways and for forming a supporting lubricant film thereon, and acooling system for directly applying to the guide surfaces of theguideways a quantity-regulated coolant in the form of the lubricant insaid lubricant circulating system.

12. Apparatus according to claim 11 wherein said cooling system includesmeans for spraying said lubricant coolant into said lubricantcirculating system.

1. Method of regulating the temperature of a form bed running onguideways in a flat bed letter-press printing machine, which comprisesmeasuring the temperature of the form bed, comparing the measured formbed temperature to a given nominal value, and selectively precooling andpreheating lubricant supplied under pressure and from below to the formbed and the guideways for the form bed so that the temperature of theform bed corresponds substantially to the given nominal value duringoperation of the printing machine.
 2. Apparatus for regulating thetemperature of a form bed running on guideways in a flat bedletter-press printing machine comprising means for measuring thetemperature of the form bed, means for comparing the form bedtemperature to a given nominal value, and means for selectivelyprecooling and preheating lubricant supplied under pressure and frombelow to the guideways and to the form bed so that the temperature ofthe form bed corresponds substantially to the given nominal value duringoperation of the printing machine.
 3. Apparatus according to claim 2comprising a circulating system for the lubricant including a coolingassembly, said circulating system having means for conveying thelubricant to the guideways and for forming a supporting lubricant filmthereon, said means for selectively precooling and preheating thelubricant being operatively connected to said cooling assembly forregulating the temperature of the lubricant at an approximately constanttemperature whereby the regulating deviation necessary for maintainingstability of the system is only a few degrees centigrade.
 4. Apparatusaccording to claim 2, wherein said cooling assembly includes a heatexchanger.
 5. Apparatus according to claim 3 including a temperaturesensing member provided at a location in said lubricant circulatingsystem downstream from the surfaces of the guideway on which saidlubricant film is formed for determining the temperature of thelubricant at said location, comparator means operatively connectedbetween said temperAture sensing member and said cooling assembly forcomparing the temperature sensed by said sensing member with a givennominal temperature and, in response thereto, actuating said coolingassembly to vary the temperature of the lubricant downstream therefromso that the measured temperature remains independent of the load withinthe limits of permissible control deviation.
 6. Apparatus according toclaim 2 comprising a circulating system for the lubricant having meansfor conveying the lubricant to the guideways and for forming asupporting lubricant film thereon, and a circulatory cooling systemincluding closed channels for circulating a lubricant coolant into andout of proximity of the guide surfaces of said guideways, saidcirculatory cooling system including a cooling assembly, said means forselectively precooling and preheating the lubricant being operativelyconnected to said cooling assembly for regulating the temperature of thelubricant in said lubricant circulating system at an approximatelyconstant value.
 7. Apparatus according to claim 6 wherein the flow ofcoolant in said circulatory cooling system is temperature regulated. 8.Apparatus according to claim 6 wherein the flow of coolant in saidcirculatory cooling system is quantity regulated.
 9. Apparatus accordingto claim 3 comprising a circulating system for the lubricant havingmeans for conveying the lubricant under pressure to the guideways andfor forming a supporting lubricant film thereon, and a cooling systemfor directly applying to the guide surfaces of said guideways atemperature-regulated coolant in the form of the lubricant in saidlubricant circulating system.
 10. Apparatus according to claim 9 whereinsaid cooling system includes means for spraying said lubricant coolantinto said lubricant circulating system.
 11. Apparatus according to claim3 comprising a circulating system for the lubricant having means forconveying the lubricant under pressure to the guideways and for forminga supporting lubricant film thereon, and a cooling system for directlyapplying to the guide surfaces of the guideways a quantity-regulatedcoolant in the form of the lubricant in said lubricant circulatingsystem.
 12. Apparatus according to claim 11 wherein said cooling systemincludes means for spraying said lubricant coolant into said lubricantcirculating system.